Had a beauty on my V6 for the last week or so. It started on a thrash to London last weekend with the car feeling like at least 2 and sometimes 3 or more cylinders were dropping out. Back home it would almost stall when trying to accelerate across roundabouts etc (not nice in busy Yeovil), but would accelerate slowly on a very light throttle, or if you revved it like crazy and slipped the clutch.
So, changed the HT leads (£82 a set from Mazda/Ford - be warned that cheaper copies may not fit properly). No change.
Next thing is to go for the distributor cap. Found a well priced supplier on the net who when I described the problem said "It's the coil for certain." Oh. On a Maz V6 the coil is in the dizzy and is not available as a spare but this company can supply them and all the main components of the distributor ie ignition module etc for a complete rebuild. I bought a kit to do the whole thing for £176 delivered next day, fitted it all and there you go, happy silky smooth V6 engine again. A distributor from Ford is £330. These guys are at www.probedistributors.co.uk and can sell you a complete unit (new or recon), plus individual parts if you want them. Highly recommended.

Just had a look at the site. It's all there. And on the ball. Only problem I have is I'm not sure what all the model numbers are. The B3 etc ?

Dunno. Mine's a V6 which is easy as there's only one listed. You could try phoning the guy - he knows his stuff.